A Lake County, Illinois, family has filed a class action lawsuit against Blue Buffalo Company Ltd. in the U.S. District Court for the Northern District of Illinois, alleging the company's grain-free dog food contributed to their dog's death from dilated cardiomyopathy. The suit was filed by The G Law Group, with co-counsel Florek Law, on behalf of plaintiffs Ryan Walsh and Diana Walsh.
The lawsuit alleges Blue Buffalo's grain-free products have been linked in scientific studies and FDA investigations to diet-related DCM and other adverse cardiac conditions in dogs. According to The G Law Group, DCM is a disease of the heart muscle that reduces its ability to pump blood effectively, often leading to heart failure and death.
The filing cites multiple FDA complaints regarding this link, as well as clinical research showing that grain-free diets — particularly those containing peas — can interfere with taurine absorption. Taurine is an amino acid essential for myocardial health. The complaint also references research showing improved heart function in dogs that switched from grain-free to grain-inclusive diets and received taurine supplementation.
The lawsuit alleges that despite thousands of FDA complaints and a growing body of research, Blue Buffalo continued to market its products as "the healthiest food possible" made with "the finest natural ingredients," and that the company was aware of DCM concerns through internal research, veterinary studies and consumer reports. The plaintiffs said they fed their Goldendoodle, Maya, Blue Buffalo Wilderness Chicken Recipe Adult High-Protein Grain-Free Dry Dog Food for years based on those representations.
According to the lawsuit, Maya was diagnosed with DCM in 2023 after exhibiting weakness, difficulty walking and cardiac arrhythmias. Veterinary testing confirmed severe heart enlargement. Despite treatment including cardiac medications and dietary changes, Maya died from congestive heart failure in October 2024 at age 10.
The G Law Group said the proposed class includes potentially millions of consumers nationwide who purchased Blue Buffalo grain-free dog food and allegedly paid a premium based on the company's health-related marketing claims. Damages sought include the cost of the food, veterinary expenses related to diagnosing and treating heart disease, medication and specialized diet costs, and injunctive relief requiring changes to Blue Buffalo's marketing practices and consumer warnings about potential health risks.
"This case is about a large corporation marketing a product as the 'best pet food possible, made with the finest natural ingredients' while ignoring evidence of serious health risks," said Simeon Genadiev of The G Law Group. "When corporations make that choice, a choice that puts profits over the health and safety of a family's pet, they must be held accountable."
DCM study: no link to grain-free pet food
The FDA effectively paused its investigation into the link between grain-free diets and canine dilated cardiomyopathy (DCM) in late 2022. As reported by Petfood Industry and confirmed by the FDA, the agency ceased providing public updates after stating they lacked sufficient evidence to establish a definitive causal link. The investigation, begun in 2018, did not definitively identify grain-free diets as a cause.
